Abstract
Purpose: :
Graft positioning during Descemet’s Membrane Endothelial Keratoplasty (DMEK) can be technically challenging due to scrolling of the graft in the anterior chamber. We aim to fabricate novel blends of poly(lactic-co-glycolic acid) (PLGA), Poly-ethylene Glycol (PEG) thermoreversible copolymer to serve as a biocompatible and biodegradable carrier to facilitate Descemet’s Membrane Endothelial Keratoplasty (DMEK).
Methods: :
The PLGA-PEG-PLGA triblock copolymer was synthesised via ring-opening polymerization using stannous octoate in argon atmosphere. Various ratios of PLGA and PEG were used. 20%, 30% and 40% w/v hydrogel solutions were made using balanced salt solution (BSS) and characterized using a rheometer as well NMR (Nuclear Magnetic Resonance) and GPC (Gel Permeation Chromatography). ex vivo biocompatibility studies were undertaken using vital dyes. DMEK preparation and manipulation using the hydrogel was undertaken to assess its ease of handling.
Results: :
PLGA-PEG-PLGA triblock copolymer was successfully synthesised as confirmed by NMR and GPC. Sol-gel transition was manipulated by altering the molecular weight of PEG. PEG 1000 led to down shifting of the transition temperature whilst PEG 1500 increased the temperature. Variations in batches were seen, however, desired sol-gel temperature was achieved by blending. There were no appreciable cytotoxicity from the hydrogel. DMEK using the hydrogel coating did not scroll and was easier to handle in preparation for grafting.
Conclusions: :
Successful synthesis of PLGA-PEG-PLGA copolymer hydrogel was achieved. Rheology showed that the desired sol-gel transition temperature was obtained, by blending. The hydrogel permitted easier manipulation of the DMEK graft and prevented it from scrolling when in solution. Moreover, the hydrogel is no only biocompatible but may aid in protecting the endothelium during surgical manipulation.
Keywords: cornea: endothelium • cornea: basic science • cornea: storage